<?php
$datum ="2012-02-01";
echo "datum = $datum<br>";
$ndatum = explode("-",$datum);
foreach($ndatum as $key => $value) {
	echo "sleutel = $key en waarde = $value<br>";
	}

$date = mktime(0, 0, 0, $ndatum[1], $ndatum[2], $ndatum[0]); 
$week = (int)date('W', $date);
echo "week = $week<br>";
?>